A cold front from the west is forecast to sweep south and east across the UK from tomorrow. A flurry of snow is expected to hit the capital and eastern England tomorrow night, with the worst set to fall between midnight and midday on Sunday.

The first country-wide Level 3 Cold Weather Alert of the season was issued by the Met Office this week. The only higher alert is Level 4, which sees normally healthy people at risk from the cold.

TfL today assured Londoners it has stockpiled an extra 22,000 tonnes of salt in its depots, taking the total to more than 100,000 tonnes. Tube and rail engineers are ready to ensure points do not become frozen.

Mayor Boris Johnson said: "Across all our roads and rails hundreds of workers are on standby to ensure that, should we receive a mega deposit of snow, we are in a position to keep the capital moving."

Britain's deep freeze has seen daytime temperatures plummet four or five degrees lower than average for February, traditionally the coldest month of the year.